(1) Field of the Invention
The invention relates to a tray for holding die-level components during the test and burn-in processes. More specifically, the invention relates to a tray which permits the orientation of die-level component carriers to be easily inverted as required by test and burn-in processes.
(2) Related Art
For years, fabricated integrated circuits have been packaged using well-known technology. The packaged components are then subjected to test and burn-in processes as part of the quality control to help insure that the components meet established specifications and do not fail easily when stressed. The packaged components are retained in trays. The Joint Electronic Device Engineering Council (JEDEC) defined dimensions of the industry standard for these trays which are known as JEDEC trays. The packaged components are removed from the trays to be inserted into a particular test or burn-in device by automated equipment, and then returned to the trays when that particular process is completed. Test and burn-in are conducted as several individual processes, each involving a particular piece of testing equipment. An operator carries trays (or stacks of trays) of components between the different pieces of equipment. The operator effectively moves the trays from one automated process to the next. Eventually when all the individual test and burn-in processes are complete, the packaged components are actually shipped to customers within those trays.
More recently with downsizing of electronic devices, demand for die-level components has increased. This is because, by eliminating the packaging, the same processing power can be achieved using only a fraction of the space. However, it is still necessary to run test and burn-in procedures with the same rigor on the die-level components as previously performed on the packaged components. To this end, carriers were developed to retain the die-level components during test and burn-in. FIG. 1a shows a top perspective view of a prior art 280 pin carrier. The carrier is comprised of a substrate 1 having a plurality of contacts 3 around an upper surface 6 of substrate 1. Substrate 1 has an internal cavity not shown to retain the die-level component. A lid 2 overlays the substrate 1 and retains the die-level component within the substrate cavity. A lid latch 4 locks the lid 2 into place. Backplate 5 sandwiches the substrate 1 between itself and the lid 2 and provides an anchor point for the lid latch 4. Die-level components are loaded into carriers and placed in JEDEC trays by automated equipment. A tray of loaded carriers is then ready to undergo test and burn-in. Unlike packaged components, the die-level components are not shipped in the trays used during test and burn-in. After test and burn-in, the die-level components are removed from the carriers by automated equipment and inserted into gel packs. The gel packs, rather than the trays, are then shipped to the end customer. This allows the carrier to be reused. The carriers are also expensive. Thus, to make it profitable to sell die-level components at all, it is important to get the cycle rate up and such that reuse of the carriers justifies their cost.
FIG. 1b shows a bottom perspective view of a carrier of FIG. 1a. Significantly, the bottom surface 7 of substrate 1 has no contact points. Thus, while these carriers were developed to be retained in the standard JEDEC trays used for the package component, some of the test and burn-in equipment requires that the carriers be handled in lid up orientation, while other of the test and burn-in equipment requires that the carriers be handled in lid down orientation. This is true because the contact points 3 exist only on top surface 6 of substrate 1. Conversely, with prior art packaged components, the leads off the package can be contacted from either the top or the bottom so no change in orientation is required as they move through the test and burn-in processes.
The required orientation changes for test and burn-in of die-level components necessitate either large capital expenditures to develop a piece of equipment to invert the orientation each time inversion is required as the components move through the test and burn-in processes, or requires an operator to spend significant time flipping each component individually before inserting the JEDEC trays of components into the next test or burn-in device. In a typical series of test and burn-in processes, it will be necessary to flip the carriers four to eight times. The carriers are relatively fragile and if dropped, are ruined. Increased handling necessarily increases the risk of components being dropped and also slows cycle time through the overall process. Assuming a new piece of capital equipment, this requires that the trays be taken to that equipment four to eight additional times, thereby significantly slowing the process over what would be required for package components. This would also require a significant capital expenditure. Thus, either option significantly increases cost and slows turnaround time of die-level components moving through the line.
In view of the foregoing, it would be desirable to have a fast, low cost way to change the orientation of carriers for die-level components, during the test and burn-in processes, without undue delay or excessive risk of dropping components.
A die-level test and burn-in flipping tray is disclosed. A tray having a plurality of pockets adapted to receive die-level carriers formed thereon is provided. The pockets are defined by four risers, one riser defining each corner of the pocket and a support at the base of each riser to support a die-level carrier disposed within the pocket. The riser and the tray are molded such that a second tray may be mated with the original tray, the second tray having pockets in one-to-one correspondence with the first tray. The mated tray pair may then be inverted causing carriers in pockets of the first tray to transition under the influence of gravity to corresponding pockets of the second tray in an orientation inverted about the z-axis.